Method and system of heat dissipation utilizing a heat pipe in combination with an extruded heat sink

ABSTRACT

In one aspect, the present invention relates to a heat-dissipation system. The heat-dissipation system includes a heat sink having a plurality of fins coupled thereto and a heat pipe having an evaporator portion and a condenser portion. The heat pipe has a heat-transfer fluid disposed therein. The evaporator portion is disposed within the heat sink and the condenser portion is disposed externally to the heat sink. A fan is arranged to circulate air over the plurality of fins and the condenser portion. A heat-transfer coefficient of the heat-transfer fluid supplements a heat-transfer coefficient of air moving over the condenser portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and incorporates by reference for any purpose the entire disclosure of, U.S. Provisional Patent Application No. 61/942,141, filed Feb. 20, 2014.

BACKGROUND

1. Field of the Invention

The present application relates generally to heat-dissipation systems and more particularly, but not by way of limitation, to heat-dissipation systems utilizing a heat pipe to maximize the heat-transfer capability of an extruded heat sink.

2. History of the Related Art

Many aspects of methods of and systems for cooling and heating utilizing heat pipes are well developed. A heat pipe is a device for transferring heat through cyclic evaporation and condensation of a liquid enclosed in a casing from which noncondensable gasses have been removed. There are, of course, significant limitations to the amount of heat a heat pipe can transfer in a given time or in a given space.

The need for thermal stabilization of electronic components is well recognized. In that regard, low profile extrusion (“LPE”) cooling devices are extremely useful in printed circuit board (PCB) level cooling of electronic components, and for use as heat exchangers in applications where space is limited and/or low weight is critical. LPE refers to a heat exchange apparatus comprising an integral piece of metal having a series of micro-extruded hollow tubes formed therein for containing a fluid. LPE's preferably have multi-void micro-extruded tubes designed to operate under pressures and temperatures required by modern environmentally safe refrigeration gases and to resist corrosion. Aspects of LPE's and their related applications in the industry are set forth and shown in the above-referenced co-pending U.S. patent application Ser. No. 09/328,183 (now U.S. Pat. No. 6,935,409), which is incorporated herein by reference.

Low profile extrusions can currently be manufactured with a profile, or height, as low as about 0.05 inches and with tubes of varying inner diameters. Of course, future advances may allow such low profile extrusions to be manufactured with an even smaller profile. Such low profile extrusions have been conventionally used in heat-exchanger applications in the automotive industry, and are commercially available in strip form (having a generally rectangular geometry) or coil form (a continuous strip coiled for efficient transport).

SUMMARY

The present application relates generally to heat-dissipation systems and more particularly, but not by way of limitation, to heat-dissipation systems utilizing a heat pipe to maximize the heat-transfer capability of an extruded heat sink. In one aspect, the present invention relates to a heat-dissipation system. The heat-dissipation system includes a heat sink having a plurality of fins coupled thereto and a heat pipe having an evaporator portion and a condenser portion. The heat pipe has a heat-transfer fluid disposed therein. The evaporator portion is disposed within the heat sink and the condenser portion is disposed externally to the heat sink. A fan is arranged to circulate air over the plurality of fins and the condenser portion. A heat-transfer coefficient of the heat-transfer fluid supplements a heat-transfer coefficient of air moving over the condenser portion.

In another aspect, the present invention relates to a method of increasing a heat-transfer capability of a heat sink. The method includes thermally exposing a heat sink to a heat-generating component. The heat sink includes a plurality of fins coupled thereto. The method further includes arranging a heat pipe through the heat sink. The heat pipe includes an evaporator portion disposed within the heat sink and a condenser portion disposed outwardly of the heat sink. The method further includes arranging a fan proximate the heat sink and the condenser portion and circulating air over the condenser portion and between adjacent ones of the plurality of fins.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and for further objects and advantages thereof, reference may now be had to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a cross-sectional view of a prior-art cooling system;

FIG. 2 is a side view of a heat-dissipation system according to an exemplary embodiment;

FIG. 3 is a cross-sectional view of the heat-dissipation system of FIG. 2 according to an exemplary embodiment;

FIG. 4 is a bottom perspective view of the heat-dissipation system of FIG. 2 according to an exemplary embodiment;

FIG. 5 is a top perspective view of the heat-dissipation system of FIG. 2 according to an exemplary embodiment;

FIG. 6 is an exploded view of the heat-dissipation system of FIG. 2 according to an exemplary embodiment;

FIG. 7 is a perspective view of a heat-dissipation system according to an exemplary embodiment;

FIG. 8 is a perspective view of a heat-dissipation system according to an exemplary embodiment;

FIG. 9A is a front perspective view of a heat-sink assembly according to an exemplary embodiment;

FIG. 9B is a rear perspective view of a heat-sink assembly according to an exemplary embodiment;

FIG. 10A is a perspective view of a heat-dissipation system according to an exemplary embodiment;

FIG. 10B is a side view of a heat-dissipation system according to an exemplary embodiment;

FIG. 10C is a cross-sectional view of a heat-dissipation system according to an exemplary embodiment;

FIG. 11A is a perspective view of a heat-dissipation system according to an exemplary embodiment;

FIG. 11B is a side view of a heat-dissipation system according to an exemplary embodiment; and

FIG. 11C is a cross-sectional view of a heat-dissipation system according to an exemplary embodiment.

DETAILED DESCRIPTION

Various embodiments of the present invention will now be described more fully with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

FIG. 1 is a cross-sectional view of a prior-art cooling system 100. A heat sink 102 is placed in thermal contact with a warm side of a thermo-electric chip 104. The heat sink 102 includes a plurality of fins 106 to facilitate heat transfer. A fan 108 circulates air between the plurality of fins 106. During operation, heat is generated by the warm side of the thermoelectric chip 104. The heat is transferred to the plurality of fins 106 of the heat sink 102 where the heat is exhausted to an atmosphere by air that is circulated by the fan 108 between the plurality of fins 106. In the arrangement shown in FIG. 1, the heat-transfer capacity of the cooling system 100 is limited by the thermal conductivity of the air that is circulated between the plurality of fins 106.

FIG. 2 is a side view of a heat-dissipation system 200. FIG. 3 is a cross-sectional view of the heat-dissipation system 200. Referring now to FIGS. 2-3, the heat-dissipation system 200 includes a heat sink 202 with a heat pipe 204 disposed therethrough. The heat sink 202 abuts a warm side of a thermoelectric element 206; however, in other embodiments, the heat sink 202 could be arranged to abut any heat-generating component. A plurality of fins 208 extend from the heat sink 202 in a direction opposite the thermoelectric element 206. The plurality of fins 208 are arranged generally parallel with respect to each other.

Still referring to FIGS. 2-3, the heat pipe 204, in a typical embodiment, is a low-profile extrusion having a plurality of micro tubes formed therein. The heat pipe 204 includes an evaporator portion 210 (shown in FIG. 5) and a condenser portion 212. The evaporator portion 210 is disposed within the heat sink 202 near an interface with the thermoelectric element 206. The evaporator portion 212 is disposed outside of the heat sink 202 away from the interface with the thermoelectric element 206. In a typical embodiment, the heat pipe 204 contains a heat-transfer fluid such as, for example, glycol, ammonia, and the like.

FIG. 4 is a bottom perspective view of the heat-dissipation system 200. FIG. 5 is a top perspective view of the heat-dissipation system 200. FIG. 6 is a cross-sectional view of the heat-dissipation system 200. Referring to FIGS. 4-6, the heat pipe 204 is generally U-shaped. A second plurality of fins 214 surround the condenser portion 212. A fan 216 is disposed adjacent to the condenser portion 212. In a typical embodiment, the fan 216 circulates air through the second plurality of fins 214, the condenser portion 212 and the plurality of fins 208.

Referring to FIGS. 2-6, during operation, heat is generated by the warm side of the thermoelectric element 206. The heat is transmitted to the heat sink 202 and the plurality of fins 208. At the same time, the heat causes the heat-transfer fluid in the evaporator portion 210 to vaporize into a gaseous phase. Vaporization of the heat-transfer fluid consumes some of the heat generated by the thermoelectric element 206. The gaseous phase travels from the evaporator portion 210 to the condenser portion 212 by way of capillary action facilitated by the plurality of micro tubes. The fan 216 circulates air through the second plurality of fins 214, the condenser portion 212, and the plurality of fins 208.

Still referring to FIGS. 2-6, air circulated by the fan 216 causes the gaseous heat-transfer fluid to condense to a liquid phase. Such a phase change facilitates exhaustion of heat to an external environment. In addition, heat transferred to the heat sink 202 and the plurality of fins 208 is exhausted by movement of air. As shown in FIGS. 2-5, the fan 216 is arranged adjacent to the condenser portion 212 and opposite the thermoelectric element 206. The fan 216 moves air around the condenser portion 212 and into the plurality of fins 208. The air then travels outwardly in a direction generally parallel to the plurality of fins 208. The heat pipe 204 supplements the heat transfer capacity of the ambient air. The addition of the heat pipe 204 thereby allows the heat sink 202 to operate with increased capacity and efficiency than if the heat pipe 204 were not present. Additionally, the heat pipe 204 allows the heat sink 202 to be of a smaller size that if the heat pipe 204 were not present.

FIG. 7 is a perspective view of a heat-dissipation system 700. The heat-dissipation system 700 includes a heat sink 702 having a heat pipe 704 disposed there through. The heat sink 702 includes a plurality of fins 706. The heat sink 702 abuts a warm side of a thermoelectric element 708; however, in other embodiments, the heat sink 702 could be arranged to abut any heat-generating component. A plurality of fins 710 extend from the heat sink 702 in a direction opposite the thermoelectric element 708. The plurality of fins 710 are arranged generally parallel with respect to each other.

Still referring to FIG. 7, the heat pipe 704, in a typical embodiment, is a low-profile extrusion having a plurality of micro tubes formed therein. The heat pipe 704 includes an evaporator portion (not shown) and a condenser portion 714. The evaporator portion is disposed within the heat sink 702 near an interface with the thermoelectric element 708. The condenser portion 714 is disposed outside of the heat sink 702 away from the interface with the thermoelectric element 708. In a typical embodiment, the heat pipe 704 contains a heat-transfer fluid such as, for example, glycol, ammonia, and the like.

Still referring to FIG. 7, the heat pipe 704 is generally L-shaped. A second plurality of fins 716 surround the condenser portion 714. A fan 718 is disposed adjacent to the plurality of fins 710. In a typical embodiment, the fan 718 directs air downwardly into the plurality of fins 710. The air then travels in a direction generally parallel to the plurality of fins 710 and across the condenser portion 714 and the second plurality of fins 716 facilitating exhaustion of heat therefrom.

FIG. 8 is a perspective view of a heat-dissipation system 800. The heat-dissipation system 800 includes a heat sink 802 having a heat pipe 804 disposed there through. The heat sink 802 includes a plurality of fins 806. The heat sink 802 abuts a warm side of a thermoelectric element 808; however, in other embodiments, the heat sink 802 could be arranged to abut any heat-generating component. A plurality of fins 810 extend from the heat sink 802 in a direction opposite the thermoelectric element 808. The plurality of fins 810 are arranged generally parallel with respect to each other.

Still referring to FIG. 8, the heat pipe 804, in a typical embodiment, is a low-profile extrusion having a plurality of micro tubes formed therein. The heat pipe 804 includes an evaporator portion and a condenser portion 814. The evaporator portion is disposed within the heat sink 802 near an abutment with the thermoelectric element 808. The condenser portion 814 is disposed outside of the heat sink 802 away from the interface with the thermoelectric element 808. In a typical embodiment, the heat pipe 804 contains a heat-transfer fluid such as, for example, glycol, ammonia, and the like.

Still referring to FIG. 8, the heat pipe 804 is generally L-shaped. A second plurality of fins 816 surround the condenser portion 814. A fan 818 is disposed adjacent to the plurality of fins 810. In a typical embodiment, the fan 818 directs air through the plurality of fins 810 and in a direction generally parallel to the plurality of fins 810. The air then travels across the condenser portion 814 and the second plurality of fins 816 facilitating exhaustion of heat therefrom.

FIG. 9A is a front perspective view of a heat-sink assembly 900. FIG. 9B is a rear perspective view of the heat dissipation system 900. the heat-sink assembly 900 includes a heat sink 902 with a heat pipe 904 disposed therethrough. The heat sink 902 abuts, for example, a warm side of a thermoelectric element (shown in FIG. 10); however, in other embodiments, the heat sink 902 could be arranged to abut any heat-generating component. A plurality of fins 908 extend from the heat sink 902 in a direction opposite, for example, a thermoelectric element. The plurality of fins 908 are arranged generally parallel with respect to each other.

Still referring to FIGS. 9A-9B, the heat pipe 904 is a low-profile extrusion having a plurality of micro tubes formed therein. By way of example, the heat pipe 904 could, in some embodiments, be a PhasePlane® heat pipe manufactured by ThermoTek, Inc. of Flower Mound, Tex. The heat pipe 904 includes an evaporator portion 910 and a condenser portion 912. The evaporator portion 910 is disposed within the heat sink 902 near an interface with, for example, the thermoelectric element. The evaporator portion 912 is disposed outside of the heat sink 902 away from the interface with the thermoelectric element 906. In a typical embodiment, the heat pipe 904 contains a heat-transfer fluid such as, for example, glycol, ammonia, and the like.

Still referring to FIGS. 9A-9B, the heat pipe 904 is generally U-shaped. A second plurality of fins 914 surround the condenser portion 912. As shown in FIG. 9B, a notch 905 is formed in the heat sink 902 to accommodate the heat pipe 904. The notch 905 facilitates direct contact of the evaporator portion 910 of the heat pipe with, for example, a warm side of a thermoelectric element (shown in FIG. 10). The flat profile of the heat pipe 904 increases contact area between the heat pipe 904 and, for example, the warm side of the thermoelectric element. Such increased contact area improves heat transfer between, for example the warm side of the thermoelectric element and the heat pipe 904. In some embodiments, a fan (not shown) is disposed adjacent to the condenser portion 912. In a typical embodiment, the fan circulates air through the second plurality of fins 914, the condenser portion 912 and the plurality of fins 908. In a typical embodiment, the heat sink 902 increases an operational thermal range of the heat pipe 904 beyond the thermal range of the heat pipe 904 if the heat sink 902 were not present.

FIG. 10A is a perspective view of a heat-dissipation system 1000. FIG. 10B is a side view of the heat-dissipation system 1000. FIG. 10C is a cross sectional view of the heat dissipation system 1000. Referring to FIGS. 10A-10C, the heat dissipation system 1000 includes the heat sink assembly 900 discussed above with reference to FIGS. 9A-9B. As shown in FIGS. 10A-10C, the heat-sink assembly 900 is arranged such that the heat pipes 902 are placed flat against the warm side 1004 of a thermoelectric element 1002. The notch 905 facilitates direct contact of the evaporator portion 910 of the heat pipe 904 with a warm side 1004 of a thermoelectric element 1002. The flat profile of the heat pipe 904 increases contact area between the heat pipe 904 and the warm side 1004 of the thermoelectric element 1002. Such increased contact area improves heat transfer between the warm side of the thermoelectric element 1002 and the heat pipe 904. As shown in FIGS. 10A-10C, the cool side 1006 of the thermoelectric element 1002 is placed in thermal contact with a manifold 1008 having a heat-transfer fluid circulating therethrough. In a typical embodiment, the manifold 1008 has a plurality of channels disposed therethough. In a typical embodiment, the plurality of channels include surface enhancements to facilitate optimal heat transfer. Such an arrangement facilitates optimization of both the warm side 1004 and the cool side 1006 of the thermoelectric element 1002.

FIG. 11A is a perspective view of a heat-dissipation system 1100. FIG. 11B is a side view of the heat-dissipation system 1100. FIG. 11C is a cross sectional view of the heat dissipation system 1100. Referring to FIGS. 11A-11C, the heat dissipation system 1100 includes the heat sink assembly 900 discussed above with reference to FIGS. 9A-9B. As shown in FIGS. 11A-11C, the heat-sink assembly 900 is arranged such that the heat pipes 902 are placed flat against the warm side 1104 of a thermoelectric element 1102. The notch 905 facilitates direct contact of the evaporator portion 910 of the heat pipe 904 with a warm side 1104 of a thermoelectric element 1102. The flat profile of the heat pipe 904 increases contact area between the heat pipe 904 and the warm side 1104 of the thermoelectric element 1102. Such increased contact area improves heat transfer between the warm side of the thermoelectric element 1102 and the heat pipe 904.

Still referring to FIGS. 11A-11C, the heat dissipation system 1100 includes a heat sink assembly 900′, which assembly is similar in construction to the heat sink assembly 900 discussed above with reference to FIGS. 9A-9B. As shown in FIGS. 11A-11C, the heat-sink assembly 900′ is arranged such that the heat pipes 902′ are placed flat against the warm side 1104′ of a thermoelectric element 1102′. The notch 905′ facilitates direct contact of the evaporator portion 910′ of the heat pipe 904′ with a warm side 1104′ of a thermoelectric element 1102′. The flat profile of the heat pipe 904′ increases contact area between the heat pipe 904′ and the warm side 1104′ of the thermoelectric element 1102′. Such increased contact area improves heat transfer between the warm side of the thermoelectric element 1102′ and the heat pipe 904′. As shown in FIGS. 11A-11C, the cool side 1106 of the thermoelectric element 1102 and the cool side 1106′ of the thermoelectric element 1102 are placed in thermal contact with a manifold 1108 having a heat-transfer fluid circulating therethrough. In a typical embodiment, the manifold 1108 has a plurality of channels disposed therethough. In a typical embodiment, the plurality of channels include surface enhancements to facilitate optimal heat transfer. Such an arrangement facilitates optimization of both the warm side 1104 and the cool side 1106 of the thermoelectric element 1102 and the warm side warm side 1104′ and the cool side 1106′ of the thermoelectric element 1102′.

The advantages of the present invention will be apparent to those skilled in the art. As described herein, the heat pipe (204, 704, 804) supplements the heat transfer capacity of the ambient air. The addition of the heat pipe (204, 704, 804) thereby allows the heat sink (202, 702, 802) to operate with increased capacity and efficiency than if the heat pipe (204, 704, 804) were not present. Additionally, the heat pipe (204, 704, 804) allows the heat sink (202, 702, 802) to be of a smaller size that if the heat pipe (204, 704, 804) were not present. In a typical embodiment, the heat sink (202, 702, 802, 902) increases an operational thermal range of the heat pipe (204, 704, 804, 904) beyond the thermal range of the heat pipe (204, 704, 804, 904) if the heat sink (202, 702, 802, 902) were not present.

Although various embodiments of the method and system of the present invention have been illustrated in the accompanying Drawings and described in the foregoing Specification, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit and scope of the invention as set forth herein. It is intended that the Specification and examples be considered as illustrative only. 

What is claimed is:
 1. A heat-dissipation system comprising: a heat sink having a first plurality of fins coupled thereto, the heat sink having a lower face for placement in contact with a heat-generating element, the heat sink comprising a notch formed in the lower face for receiving a heat pipe; the heat pipe being formed as a low-profile extrusion and comprising an evaporator portion and a condenser portion and having a heat-transfer fluid disposed therein, the evaporator portion being disposed within the notch of the heat sink such that a surface of the heat pipe is placed in contact with the heat-generating element, the condenser portion being disposed externally to the heat sink; wherein the heat sink secures the heat pipe in contact with the heat-generating element; and wherein a heat-transfer capability of the heat pipe supplements a heat-transfer capability of the heat sink.
 2. The system of claim 1, comprising a fan that circulates air downwardly through the heat sink.
 3. The system of claim 1, comprising a fan that circulates air across the heat sink.
 4. The system of claim 1, wherein the heat pipe comprises a shape selected from the group consisting of U shaped, right-angle bend, straight, and toroidal.
 5. The system of claim 1, comprising a second plurality of fins coupled to the condenser portion.
 6. The system of claim 1, wherein the second plurality of fins are aligned with the first plurality of fins.
 7. The system of claim 1, wherein the heat-generating element is a warm side of a thermoelectric element.
 8. The system of claim 7, wherein a cool side of the thermoelectric element is thermally exposed to a manifold having a plurality of channels disposed therethough, the plurality of channels having surface enhancement to facilitate optimal heat transfer.
 9. The system of claim 1, wherein vaporization of the heat-transfer fluid absorbs heat from the heat sink.
 10. The system of claim 1, wherein the heat pipe comprises a plurality of micro-tubes formed therein.
 11. The system of claim 10, wherein the plurality of micro tubes facilitate capillary movement of the heat-transfer fluid.
 12. The system of claim 1, wherein the heat sink increases an operational thermal range of the heat pipe beyond the thermal range of the heat pipe if the heat sink were not present.
 13. A method of increasing a heat-transfer capability of a heat sink, the method comprising: thermally exposing a heat sink to a heat-generating component, the heat sink comprising a first plurality of fins coupled thereto, and having a notch formed in a lower surface thereof; arranging a heat pipe through the heat sink, the heat pipe comprising a low-profile extrusion and having an evaporator portion disposed within the heat sink and a condenser portion disposed outwardly of the heat sink, the evaporator portion being received into the notch; wherein the heat sink secures the heat pipe in contact with the heat-generating element; and wherein a heat-transfer capability of the heat pipe supplements a heat-transfer capability of the heat sink.
 14. The method of claim 13, comprising arranging a second set of fins proximate the condenser portion.
 15. The method of claim 13, comprising forming the heat pipe with a plurality of micro tubes therein.
 16. The method of claim 13, comprising reducing, via the heat pipe, a size of the heat sink.
 17. The method of claim 13, comprising absorbing heat from the heat-generating component via vaporization of a heat-transfer fluid disposed in the heat pipe.
 18. The method of claim 13, comprising circulating, via a fan, air over the heat sink and the condenser portion.
 19. A heat-dissipation system comprising: a first heat sink having a plurality of fins coupled thereto, the first heat sink having a first lower face for placement in contact with a warm side of a first thermoelectric element, the first heat sink comprising a notch formed in the lower face for receiving a first heat pipe; the first heat pipe being formed as a low-profile extrusion and comprising an evaporator portion and a condenser portion, the first heat pipe having a heat-transfer fluid disposed therein, the evaporator portion being disposed within the notch of the first heat sink such that a surface of the first heat pipe is placed in contact with the warm side of the first thermoelectric element, the condenser portion being disposed externally to the heat sink; a manifold having a second heat-transfer fluid disposed therein, the manifold being placed in thermal contact with a cool side of the first thermoelectric element; wherein the heat sink secures the first heat pipe in contact with the first thermoelectric element; and wherein a heat-transfer capability of the first heat pipe supplements a heat-transfer capability of the first heat sink.
 20. The heat-dissipation system of claim 19, comprising: a second heat sink having a plurality of fins coupled thereto, the second heat sink having a second lower face for placement in contact with a warm side of a second thermoelectric element, the second heat sink comprising a notch formed in the lower face for receiving a second heat pipe; the second heat pipe being formed as a low-profile extrusion and comprising an evaporator portion and a condenser portion, the second heat pipe having a heat-transfer fluid disposed therein, the evaporator portion being disposed within the notch of the second heat sink such that a surface of the second heat pipe is placed in contact with the warm side of the second thermoelectric element, the condenser portion being disposed externally to the heat sink; a cool side of the second thermoelectric element being placed in thermal contact with the manifold; wherein the heat sink secures the second heat pipe in contact with the second thermoelectric element; and wherein a heat-transfer capability of the second heat pipe supplements a heat-transfer capability of the second heat sink. 